POS0215 CLASSIC VERSUS ATYPICAL POLYMYALGIA RHEUMATICA: TWO SIDES OF THE SAME COIN OR MISCLASSIFICATION?
Authors: Y. El Miedany, M. Toth, M. Elgaafary, S. Bahlas, M. H. Abu-Zaid, W. Hassan, S. A. A. Tabra, W. Elwakil, S. Saber, N. Kamel
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> PMR is usually diagnosed based on the patient's clinical history and confirmed by the presence of an elevated inflammatory markers ESR and CRP. Once the diagnosis is confirmed, steroid therapy is commenced, and their response is usually rapid and dramatic. However, sometimes patients may present with symptoms similar to PMR but do not meet the 2012 EULAR/ACR criteria. It is not well known if these atypical patients represent a subtype of PMR or another musculoskeletal inflammatory condition. <h3>Objectives</h3> 1. to compare the clinical, laboratory and sonographic patterns in patients presenting with classic PMR versus those with atypical PMR symptoms. 2. To assess whether ultrasonography of the shoulders and hips has added value for PMR subclassification. <h3>Methods</h3> Longitudinal multi-center prospective study of patients presenting with PMR symptoms and their respective US scans of the shoulders and hips. The patients were stratified into a cohort of classic PMR who meet the 2012 EULAR/ACR criteria; and a group of atypical PMR presenting with symptoms similar to classic PMR but did not fulfil the 2012 EULAR/ACR criteria. Every patient was assessed clinically, had blood tests for ESR, CRP, basic rheumatology blood profile, urine analysis (to rule out microscopic hematuria), CK, bone profile, rheumatoid factor, anti-CCP, ANA, TSH and HbA1c. US scan was carried out for both shoulders and hips. The patients were treated according to agreed protocol and monitored for 12-months. <h3>Results</h3> 104 patients (68 women and 36 men) with a mean age±SD of 63.2±9.7 years. Eighty-one (84/104) patients had classic PMR and 20 (19.3%) atypical PMR. Patients with atypical PMR had shorter duration of symptoms (8.1 + 1.3 Vs 14.6 + 1.5 weeks). In the atypical PMR patients, pain in the hip/pelvic girdle was more frequent (100% vs 60.1%), whereas shoulder girdle pain was less (50% vs 98), in comparison to the classic PMR patients. Arthritis was less common in the atypical PMR cohort (15% Vs 42%), similarly GCA was less prevalent in the atypical PMR (5% Vs 20.2%). Patients with classic PMR were more likely to have bilateral abnormal ultrasound findings in the shoulder (particularly subdeltoid bursitis [92%] and biceps tenosynovitis [83.3%]), as well as in the hips [78.6%] than the atypical PMR subjects where US findings tend to be unilateral (shoulder 50% and the hip 75%). Systematic symptoms: fatigue, weight loss, fever were more common in the classic PMR than atypical PMR (%). No significant difference on comparing morning stiffness in both groups. Both patients' groups responded very well to steroid therapy with significant improvement in the symptoms in 2-4 weeks' time. <h3>Conclusion</h3> Patients with atypical PMR could represent an early form of the classic PMR. Atypical PMR used to have a shorter evolution of symptoms, have predominantly hip/pelvic girdle affection. US of the shoulders and hips may have an added value for stratifying PMR patients and differentiating atypical PMR from other musculoskeletal conditions. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.